Fix use-after-free around DISTINCT transition function calls.
Have tuplesort_gettupleslot() copy the contents of its current table slot
as needed. This is based on an approach taken by tuplestore_gettupleslot().
In the future, tuplesort_gettupleslot() may also be taught to avoid copying
the tuple where caller can determine that that is safe (the
tuplestore_gettupleslot() interface already offers this option to callers).
Patch by Peter Geoghegan. Fixes bug #14344, reported by Regina Obe.
Replace PostmasterRandom() with a stronger way of generating randomness.
This adds a new routine, pg_strong_random() for generating random bytes,
for use in both frontend and backend. At the moment, it's only used in
the backend, but the upcoming SCRAM authentication patches need strong
random numbers in libpq as well.
pg_strong_random() is based on, and replaces, the existing implementation
in pgcrypto. It can acquire strong random numbers from a number of sources,
depending on what's available:
- OpenSSL RAND_bytes(), if built with OpenSSL
- On Windows, the native cryptographic functions are used
- /dev/urandom
- /dev/random
Original patch by Magnus Hagander, with further work by Michael Paquier
and me.
Andres Freund [Sat, 15 Oct 2016 00:22:51 +0000 (17:22 -0700)]
Use more efficient hashtable for execGrouping.c to speed up hash aggregation.
The more efficient hashtable speeds up hash-aggregations with more than
a few hundred groups significantly. Improvements of over 120% have been
measured.
Due to the the different hash table queries that not fully
determined (e.g. GROUP BY without ORDER BY) may change their result
order.
The conversion is largely straight-forward, except that, due to the
static element types of simplehash.h type hashes, the additional data
some users store in elements (e.g. the per-group working data for hash
aggregaters) is now stored in TupleHashEntryData->additional. The
meaning of BuildTupleHashTable's entrysize (renamed to additionalsize)
has been changed to only be about the additionally stored size. That
size is only used for the initial sizing of the hash-table.
Reviewed-By: Tomas Vondra
Discussion: <20160727004333.r3e2k2y6fvk2ntup@alap3.anarazel.de>
Andres Freund [Fri, 14 Oct 2016 23:05:30 +0000 (16:05 -0700)]
Use more efficient hashtable for tidbitmap.c to speed up bitmap scans.
Use the new simplehash.h to speed up tidbitmap.c uses. For bitmap scan
heavy queries speedups of over 100% have been measured. Both lossy and
exact scans benefit, but the wins are bigger for mostly exact scans.
The conversion is mostly trivial, except that tbm_lossify() now restarts
lossifying at the point it previously stopped. Otherwise the hash table
becomes unbalanced because the scan in done in hash-order, leaving the
end of the hashtable more densely filled then the beginning. That caused
performance issues with dynahash as well, but due to the open chaining
they were less pronounced than with the linear adressing from
simplehash.h.
Reviewed-By: Tomas Vondra
Discussion: <20160727004333.r3e2k2y6fvk2ntup@alap3.anarazel.de>
Andres Freund [Fri, 14 Oct 2016 23:05:30 +0000 (16:05 -0700)]
Add a macro templatized hashtable.
dynahash.c hash tables aren't quite fast enough for some
use-cases. There are several reasons for lacking performance:
- the use of chaining for collision handling makes them cache
inefficient, that's especially an issue when the tables get bigger.
- as the element sizes for dynahash are only determined at runtime,
offset computations are somewhat expensive
- hash and element comparisons are indirect function calls, causing
unnecessary pipeline stalls
- it's two level structure has some benefits (somewhat natural
partitioning), but increases the number of indirections
to fix several of these the hash tables have to be adjusted to the
individual use-case at compile-time. C unfortunately doesn't provide a
good way to do compile code generation (like e.g. c++'s templates for
all their weaknesses do). Thus the somewhat ugly approach taken here is
to allow for code generation using a macro-templatized header file,
which generates functions and types based on a prefix and other
parameters.
Later patches use this infrastructure to use such hash tables for
tidbitmap.c (bitmap scans) and execGrouping.c (hash aggregation,
...). In queries where these use up a large fraction of the time, this
has been measured to lead to performance improvements of over 100%.
There are other cases where this could be useful (e.g. catcache.c).
The hash table design chosen is a variant of linear open-addressing. The
biggest disadvantage of simple linear addressing schemes are highly
variable lookup times due to clustering, and deletions leaving a lot of
tombstones around. To address these issues a variant of "robin hood"
hashing is employed. Robin hood hashing optimizes chaining lengths by
moving elements close to their optimal bucket ("rich" elements), out of
the way if a to-be-inserted element is further away from its optimal
position (i.e. it's "poor"). While that can make insertions slower, the
average lookup performance is a lot better, and higher fill factors can
be used in a still performant manner. To avoid tombstones - which
normally solve the issue that a deleted node's presence is relevant to
determine whether a lookup needs to continue looking or is done -
buckets following a deleted element are shifted backwards, unless
they're empty or already at their optimal position.
There's further possible improvements that can be made to this
implementation. Amongst others:
- Use distance as a termination criteria during searches. This is
generally a good idea, but I've been able to see the overhead of
distance calculations in some cases.
- Consider combining the 'empty' status into the hashvalue, and enforce
storing the hashvalue. That could, in some cases, increase memory
density and remove a few instructions.
- Experiment further with the, very conservatively choosen, fillfactor.
- Make maximum size of hashtable configurable, to allow storing very
very large tables. That'd require 64bit hash values to be more common
than now, though.
- some smaller memcpy calls could be optimized to copy larger chunks
But since the new implementation is already considerably faster than
dynahash it seem sensible to start using it.
Reviewed-By: Tomas Vondra
Discussion: <20160727004333.r3e2k2y6fvk2ntup@alap3.anarazel.de>
Andres Freund [Fri, 14 Oct 2016 23:05:30 +0000 (16:05 -0700)]
Add likely/unlikely() branch hint macros.
These are useful for very hot code paths. Because it's easy to guess
wrongly about likelihood, and because such likelihoods change over time,
they should be used sparingly.
Past tests have shown it'd be a good idea to use them in some places,
e.g. in error checks around ereports that ERROR out, but that's work for
later.
Tom Lane [Fri, 14 Oct 2016 20:28:34 +0000 (16:28 -0400)]
Fix assorted integer-overflow hazards in varbit.c.
bitshiftright() and bitshiftleft() would recursively call each other
infinitely if the user passed INT_MIN for the shift amount, due to integer
overflow in negating the shift amount. To fix, clamp to -VARBITMAXLEN.
That doesn't change the results since any shift distance larger than the
input bit string's length produces an all-zeroes result.
Also fix some places that seemed inadequately paranoid about input typmods
exceeding VARBITMAXLEN. While a typmod accepted by anybit_typmodin() will
certainly be much less than that, at least some of these spots are
reachable with user-chosen integer values.
Tom Lane [Thu, 13 Oct 2016 23:45:58 +0000 (19:45 -0400)]
Fix handling of pgstat counters for TRUNCATE in a prepared transaction.
pgstat_twophase_postcommit is supposed to duplicate the math in
AtEOXact_PgStat, but it had missed out the bit about clearing
t_delta_live_tuples/t_delta_dead_tuples for a TRUNCATE.
It's harder than you might think to replicate the issue here, because
those counters would only be nonzero when a previous transaction in
the same backend had added/deleted tuples in the truncated table,
and those counts hadn't been sent to the stats collector yet.
Evident oversight in commit d42358efb. I've not added a regression
test for this; we tried to add one in d42358efb, and had to revert it
because it was too timing-sensitive for the buildfarm.
Tom Lane [Thu, 13 Oct 2016 21:05:14 +0000 (17:05 -0400)]
Fix another bug in merging of inherited CHECK constraints.
It's not good for an inherited child constraint to be marked connoinherit;
that would result in the constraint not propagating to grandchild tables,
if any are created later. The code mostly prevented this from happening
but there was one case that was missed.
This is somewhat related to commit e55a946a8, which also tightened checks
on constraint merging. Hence, back-patch to 9.2 like that one. This isn't
so much because there's a concrete feature-related reason to stop there,
as to avoid having more distinct behaviors than we have to in this area.
Tom Lane [Thu, 13 Oct 2016 20:08:16 +0000 (16:08 -0400)]
Remove dead code in pg_dump.
I'm not sure if this provision for "pg_backup" behaving a bit differently
from "pg_dump" ever did anything useful in a released version. But it's
definitely dead code now.
Tom Lane [Thu, 13 Oct 2016 19:06:46 +0000 (15:06 -0400)]
Try to find out the actual hugepage size when making a MAP_HUGETLB request.
Even if Linux's mmap() is okay with a partial-hugepage request, munmap()
is not, as reported by Chris Richards. Therefore it behooves us to try
a bit harder to find out the actual hugepage size, instead of assuming
that we can skate by with a guess.
For the moment, just look into /proc/meminfo to find out the default
hugepage size, and use that. Later, on kernels that support requests
for nondefault sizes, we might try to consider other alternatives.
But that smells more like a new feature than a bug fix, especially if
we want to provide any way for the DBA to control it, so leave it for
another day.
I set this up to allow easy addition of platform-specific code for
non-Linux platforms, if needed; but right now there are no reports
suggesting that we need to work harder on other platforms.
Back-patch to 9.4 where hugepage support was introduced.
Tom Lane [Thu, 13 Oct 2016 17:59:56 +0000 (13:59 -0400)]
Clean up handling of anonymous mmap'd shared-memory segment.
Fix detaching of the mmap'd segment to have its own on_shmem_exit callback,
rather than piggybacking on the one for detaching from the SysV segment.
That was confusing, and given the distance between the two attach calls,
it was trouble waiting to happen.
Make the detaching calls idempotent by clearing AnonymousShmem to show
we've already unmapped. I spent quite a bit of time yesterday trying
to find a path that would allow the munmap()'s to be done twice, and
while I did not succeed, it seems silly that there's even a question.
Make the #ifdef logic less confusing by separating "do we want to use
anonymous shmem" from EXEC_BACKEND. Even though there's no current
scenario where those conditions are different, it is not helpful for
different places in the same file to be testing EXEC_BACKEND for what
are fundamentally different reasons.
Don't do on_exit_reset() in StartBackgroundWorker(). At best that's
useless (InitPostmasterChild would have done it already) and at worst
it could zap some callback that's unrelated to shared memory.
Improve comments, and simplify the huge_pages enablement logic slightly.
Back-patch to 9.4 where hugepage support was introduced.
Arguably this should go into 9.3 as well, but the code looks
significantly different there, and I doubt it's worth the
trouble of adapting the patch given I can't show a live bug.
Tom Lane [Thu, 13 Oct 2016 14:46:22 +0000 (10:46 -0400)]
Fix pg_dumpall regression test to be locale-independent.
The expected results in commit b4fc64578 seem to have been generated
in a non-C locale, which just points up the fact that the ORDER BY
clause was locale-sensitive.
Tom Lane [Thu, 13 Oct 2016 04:25:28 +0000 (00:25 -0400)]
Fix broken jsonb_set() logic for replacing array elements.
Commit 0b62fd036 did a fairly sloppy job of refactoring setPath()
to support jsonb_insert() along with jsonb_set(). In its defense,
though, there was no regression test case exercising the case of
replacing an existing element in a jsonb array.
Per bug #14366 from Peng Sun. Back-patch to 9.6 where bug was introduced.
Andres Freund [Thu, 13 Oct 2016 01:31:45 +0000 (18:31 -0700)]
Fix further hash table order dependent tests.
Similar to 0137caf273, this makes contrib and pl tests less dependant on
hash-table order. After this commit, at least some order affecting
changes to execGrouping.c don't result in regression test changes
anymore.
Tom Lane [Wed, 12 Oct 2016 22:01:43 +0000 (18:01 -0400)]
Revert addition of PGDLLEXPORT in PG_FUNCTION_INFO_V1 macro.
This turns out not to be as harmless as I thought: MSVC will complain
if it sees an "extern" declaration without PGDLLEXPORT and then one with.
(Seems fairly silly, given that this can be changed after the fact by the
linker, but there you have it.) Therefore, contrib modules that have
extern's for V1 functions in header files are falling over in the
buildfarm, since none of those externs are marked PGDLLEXPORT.
We might or might not conclude that we're willing to plaster those
declarations with PGDLLEXPORT in HEAD, but in any case there's no way we're
going to ship this change in the back branches. Third-party authors would
not thank us for breaking their code in a minor release. Hence, revert
the addition of PGDLLEXPORT (but let's keep the extra info in the comment).
If we do the other changes we can revert this commit in HEAD.
Tom Lane [Wed, 12 Oct 2016 19:11:31 +0000 (15:11 -0400)]
pg_dump's getTypes() needn't retrieve typinput or typoutput anymore.
Commit 64f3524e2 removed the stanza of code that examined these values.
I failed to notice they were unnecessary because my compiler didn't
warn about the un-read variables. Noted by Peter Eisentraut.
Tom Lane [Wed, 12 Oct 2016 18:54:08 +0000 (14:54 -0400)]
Remove unnecessary int2vector-specific hash function and equality operator.
These functions were originally added in commit d8cedf67a to support
use of int2vector columns as catcache lookup keys. However, there are
no catcaches that use such columns. (Indeed I now think it must always
have been dead code: a catcache with such a key column would need an
underlying unique index on the column, but we've never had an int2vector
btree opclass.)
Getting rid of the int2vector-specific operator and function does not
lose any functionality, because operations on int2vectors will now fall
back to the generic anyarray support. This avoids a wart that a btree
index on an int2vector column (made using anyarray_ops) would fail to
match equality searches, because int2vectoreq wasn't a member of the
opclass. We don't really care much about that, since int2vector is not
meant as a type for users to use, but it's silly to have extra code and
less functionality.
If we ever do want a catcache to be indexed by an int2vector column,
we'd need to put back full btree and hash opclasses for int2vector,
comparable to the support for oidvector. (The anyarray code can't be
used at such a low level, because it needs to do catcache lookups.)
But we'll deal with that if/when the need arises.
Also worth noting is that removal of the hash int2vector_ops opclass will
break any user-created hash indexes on int2vector columns. While hash
anyarray_ops would serve the same purpose, it would probably not compute
the same hash values and thus wouldn't be on-disk-compatible. Given that
int2vector isn't a user-facing type and we're planning other incompatible
changes in hash indexes for v10 anyway, this doesn't seem like something
to worry about, but it's probably worth mentioning here.
Tom Lane [Wed, 12 Oct 2016 16:45:50 +0000 (12:45 -0400)]
Provide DLLEXPORT markers for C functions via PG_FUNCTION_INFO_V1 macro.
This isn't really necessary for our own code, because we use a .DEF file
in MSVC builds (see gendef.pl), or --export-all-symbols in MinGW and
Cygwin builds, to ensure that all global symbols in loadable modules
will be exported on Windows. However, third-party authors might use
different build processes that need this marker, and it's harmless
enough for our own builds.
To some extent, this is an oversight in commit e7128e8db, so back-patch
to 9.4 where that was added.
Tom Lane [Wed, 12 Oct 2016 16:19:56 +0000 (12:19 -0400)]
Remove pg_dump/pg_dumpall support for dumping from pre-8.0 servers.
The need for dumping from such ancient servers has decreased to about nil
in the field, so let's remove all the code that catered to it. Aside
from removing a lot of boilerplate variant queries, this allows us to not
have to cope with servers that don't have (a) schemas or (b) pg_depend.
That means we can get rid of assorted squishy code around that. There
may be some nonobvious additional simplifications possible, but this patch
already removes about 1500 lines of code.
I did not remove the ability for pg_restore to read custom-format archives
generated by these old versions (and light testing says that that does
still work). If you have an old server, you probably also have a pg_dump
that will work with it; but you have an old custom-format backup file,
that might be all you have.
It'd be possible at this point to remove fmtQualifiedId()'s version
argument, but I refrained since that would affect code outside pg_dump.
Pass the buffer size as argument to LogicalTapeRewindForRead, rather than
setting it earlier with the separate LogicTapeAssignReadBufferSize call.
This way, the buffer size is set closer to where it's actually used, which
makes the code easier to understand.
This makes the calculation for how much memory to use for the buffers less
precise. We now use the same amount of memory for every tape, rounded down
to the nearest BLCKSZ boundary, instead of using one more block for some
tapes, to get the total up to exact amount of memory available. That should
be OK, merging isn't too sensitive to the exact amount of memory used.
Tom Lane [Tue, 11 Oct 2016 16:19:18 +0000 (12:19 -0400)]
Drop server support for FE/BE protocol version 1.0.
While this isn't a lot of code, it's been essentially untestable for
a very long time, because libpq doesn't support anything older than
protocol 2.0, and has not since release 6.3. There's no reason to
believe any other client-side code still uses that protocol, either.
Tom Lane [Tue, 11 Oct 2016 15:26:04 +0000 (11:26 -0400)]
Remove "sco" and "unixware" ports.
SCO OpenServer and SCO UnixWare are more or less dead platforms.
We have never had a buildfarm member testing the "sco" port, and
the last "unixware" member was last heard from in 2012, so it's
fair to doubt that the code even compiles anymore on either one.
Remove both ports. We can always undo this if someone shows up
with an interest in maintaining and testing these platforms.
Tom Lane [Tue, 11 Oct 2016 14:08:45 +0000 (10:08 -0400)]
Improve documentation for CREATE RECURSIVE VIEW.
It was perhaps not entirely clear that internal self-references shouldn't
be schema-qualified even if the view name is written with a schema.
Spell it out.
Tom Lane [Mon, 10 Oct 2016 19:11:33 +0000 (15:11 -0400)]
Update user docs for switch to POSIX semaphores.
Since commit ecb0d20a9 hasn't crashed and burned, here's the promised
docs update for it.
In addition to explaining that Linux and FreeBSD ports now use POSIX
semaphores, I did some wordsmithing on pre-existing wording; in
particular trying to clarify which SysV parameters need to be set with
an eye to total usage across all applications.
Andres Freund [Mon, 10 Oct 2016 20:41:57 +0000 (13:41 -0700)]
Make regression tests less dependent on hash table order.
Upcoming changes to the hash table code used, among others, for grouping
and set operations will change the output order for a few queries. To
make it less likely that actual bugs are hidden between regression test
ordering changes, and to make the tests robust against platform
dependant ordering, add ORDER BYs guaranteeing the output order.
As it's possible that some of the changes expose platform dependant
ordering, push this earlier, to let the buildfarm shake out potentially
unstable results.
Tom Lane [Mon, 10 Oct 2016 14:35:58 +0000 (10:35 -0400)]
In PQsendQueryStart(), avoid leaking any left-over async result.
Ordinarily there would not be an async result sitting around at this
point, but it appears that in corner cases there can be. Considering
all the work we're about to launch, it's hardly going to cost anything
noticeable to check.
It's been like this forever, so back-patch to all supported branches.
Tom Lane [Sun, 9 Oct 2016 22:03:45 +0000 (18:03 -0400)]
Use unnamed POSIX semaphores, if available, on Linux and FreeBSD.
We've had support for using unnamed POSIX semaphores instead of System V
semaphores for quite some time, but it was not used by default on any
platform. Since many systems have rather small limits on the number of
SysV semaphores allowed, it seems desirable to switch to POSIX semaphores
where they're available and don't create performance or kernel resource
problems. Experimentation by me shows that unnamed POSIX semaphores
are at least as good as SysV semaphores on Linux, and we previously had
a report from Maksym Sobolyev that FreeBSD is significantly worse with
SysV semaphores than POSIX ones. So adjust those two platforms to use
unnamed POSIX semaphores, if configure can find the necessary library
functions. If this goes well, we may switch other platforms as well,
but it would be advisable to test them individually first.
It's not currently contemplated that we'd encourage users to select
a semaphore API for themselves, but anyone who wants to experiment
can add PREFERRED_SEMAPHORES=UNNAMED_POSIX (or NAMED_POSIX, or SYSV)
to their configure command line to do so.
I also tweaked configure to report which API it's selected, mainly
so that we can tell that from buildfarm reports.
I did not touch the user documentation's discussion about semaphores;
that will need some adjustment once the dust settles.
Tom Lane [Sun, 9 Oct 2016 16:49:37 +0000 (12:49 -0400)]
Fix incorrect handling of polymorphic aggregates used as window functions.
The transfunction was told that its first argument and result were
of the window function output type, not the aggregate state type.
This'd only matter if the transfunction consults get_fn_expr_argtype,
which typically only polymorphic functions would do.
Although we have several regression tests around polymorphic aggs,
none of them detected this mistake --- in fact, they still didn't
fail when I injected the same mistake into nodeAgg.c. So add some
more tests covering both plain agg and window-function-agg cases.
Per report from Sebastian Luque. Back-patch to 9.6 where the error
was introduced (by sloppy refactoring in commit 804163bc2, looks like).
Tom Lane [Sat, 8 Oct 2016 23:29:27 +0000 (19:29 -0400)]
Fix two bugs in merging of inherited CHECK constraints.
Historically, we've allowed users to add a CHECK constraint to a child
table and then add an identical CHECK constraint to the parent. This
results in "merging" the two constraints so that the pre-existing
child constraint ends up with both conislocal = true and coninhcount > 0.
However, if you tried to do it in the other order, you got a duplicate
constraint error. This is problematic for pg_dump, which needs to issue
separated ADD CONSTRAINT commands in some cases, but has no good way to
ensure that the constraints will be added in the required order.
And it's more than a bit arbitrary, too. The goal of complaining about
duplicated ADD CONSTRAINT commands can be served if we reject the case of
adding a constraint when the existing one already has conislocal = true;
but if it has conislocal = false, let's just make the ADD CONSTRAINT set
conislocal = true. In this way, either order of adding the constraints
has the same end result.
Another problem was that the code allowed creation of a parent constraint
marked convalidated that is merged with a child constraint that is
!convalidated. In this case, an inheritance scan of the parent table could
emit some rows violating the constraint condition, which would be an
unexpected result given the marking of the parent constraint as validated.
Hence, forbid merging of constraints in this case. (Note: valid child and
not-valid parent seems fine, so continue to allow that.)
Per report from Benedikt Grundmann. Back-patch to 9.2 where we introduced
possibly-not-valid check constraints. The second bug obviously doesn't
apply before that, and I think the first doesn't either, because pg_dump
only gets into this situation when dealing with not-valid constraints.
Tom Lane [Sat, 8 Oct 2016 01:12:25 +0000 (21:12 -0400)]
libpqwalreceiver needs to link with libintl when using --enable-nls.
The need for this was previously obscured even on picky platforms
by the hack we used to support direct cross-module references in
the transforms contrib modules. Now that that hack is gone, the
undefined symbol is exposed, as reported by Robert Haas.
Back-patch to 9.5 where we started to use -Wl,-undefined,dynamic_lookup.
I'm a bit surprised that the older branches don't seem to contain
any gettext references in this module, but since they don't fail
at build time, they must not. (We might be able to get away with
leaving this alone in 9.5/9.6, but I think it's cleaner if the
reference gets resolved at link time.)
Andres Freund [Fri, 7 Oct 2016 23:55:15 +0000 (16:55 -0700)]
Fix fallback implementation of pg_atomic_write_u32().
I somehow had assumed that in the spinlock (in turn possibly using
semaphores) based fallback atomics implementation 32 bit writes could be
done without a lock. As far as the write goes that's correct, since
postgres supports only platforms with single-copy atomicity for aligned
32bit writes. But writing without holding the spinlock breaks
read-modify-write operations like pg_atomic_compare_exchange_u32(),
since they'll potentially "miss" a concurrent write, which can't happen
in actual hardware implementations.
In 9.6+ when using the fallback atomics implementation this could lead
to buffer header locks not being properly marked as released, and
potentially some related state corruption. I don't see a related danger
in 9.5 (earliest release with the API), because pg_atomic_write_u32()
wasn't used in a concurrent manner there.
The state variable of local buffers, before this change, were
manipulated using pg_atomic_write_u32(), to avoid unnecessary
synchronization overhead. As that'd not be the case anymore, introduce
and use pg_atomic_unlocked_write_u32(), which does not correctly
interact with RMW operations.
This bug only caused issues when postgres is compiled on platforms
without atomics support (i.e. no common new platform), or when compiled
with --disable-atomics, which explains why this wasn't noticed in
testing.
Reported-By: Tom Lane
Discussion: <14947.1475690465@sss.pgh.pa.us>
Backpatch: 9.5-, where the atomic operations API was introduced.
Remove bogus mapping from UTF-8 to SJIS conversion table.
0xc19c is not a valid UTF-8 byte sequence. It doesn't do any harm, AFAICS,
but it's surely not intentional. No backpatching though, just to be sure.
In the passing, also add a file header comment to the file, like the
UCS_to_SJIS.pl script would produce. (The file was originally created with
UCS_to_SJIS.pl, but has been modified by hand since then. That's
questionable, but I'll leave fixing that for later.)
Make TAP test suites to work, when @INC does not contain current dir.
Recent Perl and/or new Linux distributions are starting to remove "." from
the @INC list by default. That breaks pg_rewind and ssl test suites, which
use helper perl modules that reside in the same directory. To fix, add the
current source directory explicitly to prove's include dir.
The vcregress.pl script probably also needs something like this, but I
wasn't able to remove '.' from @INC on Windows to test this, and don't want
to try doing that blindly.
Tom Lane [Fri, 7 Oct 2016 15:27:34 +0000 (11:27 -0400)]
Fix python shlib probe for Cygwin.
On buildfarm member cockatiel, that library is in /usr/bin.
(Possibly we should look at $PATH on this platform?)
Per off-list report from Andrew Dunstan.
Tom Lane [Fri, 7 Oct 2016 13:51:18 +0000 (09:51 -0400)]
Fix pg_dump to work against pre-9.0 servers again.
getBlobs' queries for pre-9.0 servers were broken in two ways:
the 7.x/8.x query uses DISTINCT so it can't have unspecified-type
NULLs in the target list, and both that query and the 7.0 one
failed to provide the correct output column labels, so that the
subsequent code to extract data from the PGresult would fail.
Back-patch to 9.6 where the breakage was introduced (by commit 23f34fa4b).
Clear OpenSSL error queue after failed X509_STORE_load_locations() call.
Leaving the error in the error queue used to be harmless, because the
X509_STORE_load_locations() call used to be the last step in
initialize_SSL(), and we would clear the queue before the next
SSL_connect() call. But previous commit moved things around. The symptom
was that if a CRL file was not found, and one of the subsequent
initialization steps, like loading the client certificate or private key,
failed, we would incorrectly print the "no such file" error message from
the earlier X509_STORE_load_locations() call as the reason.
Backpatch to all supported versions, like the previous patch.
1. There was a race condition, if two threads opened a connection at the
same time. We used a mutex around SSL_CTX_* calls, but that was not
enough, e.g. if one thread SSL_CTX_load_verify_locations() with one
path, and another thread set it with a different path, before the first
thread got to establish the connection.
2. Opening two different connections, with different sslrootcert settings,
seemed to fail outright with "SSL error: block type is not 01". Not sure
why.
3. We created the SSL object, before calling SSL_CTX_load_verify_locations
and SSL_CTX_use_certificate_chain_file on the SSL context. That was
wrong, because the options set on the SSL context are propagated to the
SSL object, when the SSL object is created. If they are set after the
SSL object has already been created, they won't take effect until the
next connection. (This is bug #14329)
At least some of these could've been fixed while still using a shared
context, but it would've been more complicated and error-prone. To keep
things simple, let's just use a separate SSL context for each connection,
and accept the overhead.
If you point pg_rewind to a server that is using synchronous replication,
with "pg_rewind --source-server=...", and the replication is not working
for some reason, pg_rewind will get stuck because it creates a temporary
table, which needs to be replicated. You could call broken replication a
pilot error, but pg_rewind is often used in special circumstances, when
there are changes to the replication setup.
We don't do any "real" updates, and we don't care about fsyncing or
replicating the operations on the temporary tables, so fix that by
setting synchronous_commit off.
Michael Banck, Michael Paquier. Backpatch to 9.5, where pg_rewind was
introduced.
Fix excessive memory consumption in the new sort pre-reading code.
LogicalTapeRewind() should not allocate large read buffer, if the tape
is completely empty. The calling code relies on that, for its
calculation of how much memory to allocate for the read buffers. That
lead to massive overallocation of memory, if maxTapes was high, but
only a few tapes were actually used.
Tom Lane [Thu, 6 Oct 2016 03:03:55 +0000 (23:03 -0400)]
Remove -Wl,-undefined,dynamic_lookup in macOS build.
We don't need this anymore, and it prevents build-time error checking
that's usually good to have, so remove it. Undoes one change of commit cac765820.
Unfortunately, it's much harder to get a similar effect on other common
platforms, because we don't want the linker to throw errors for symbols
that will be resolved in the core backend. Only macOS and AIX expect the
core backend executable to be available while linking loadable modules,
so only these platforms can usefully throw errors for unresolved symbols
at link time.
Tom Lane [Thu, 6 Oct 2016 02:47:23 +0000 (22:47 -0400)]
Try to fix python shlib probe for MinGW.
Per discussion with Andrew Dunstan, it seems there are three peculiarities
of the Python installation on MinGW (or at least, of the instance on
buildfarm member frogmouth). First, the library name doesn't contain
"2.7" but just "27". It looks like we can deal with that by consulting
get_config_vars('VERSION') to see whether a dot should be used or not.
Second, the library might be in c:/Windows/System32, analogously to it
possibly being in /usr/lib on Unix-oid platforms. Third, it's apparently
not standard to use the prefix "lib" on the file name. This patch will
accept files with or without "lib", but the first part of that may well
be dead code.
Tom Lane [Wed, 5 Oct 2016 15:44:57 +0000 (11:44 -0400)]
In python shlib probe, cater for OpenBSD, which omits the .so symlink.
Most Unix-oid platforms provide a symlink "libfoo.so" -> "libfoo.so.n.n"
to allow the linker to resolve a reference "-lfoo" to a version-numbered
shared library. OpenBSD has apparently hacked ld(1) to do this internally,
because there are no such symlinks to be found in their library
directories. Tweak the new code in PGAC_CHECK_PYTHON_EMBED_SETUP to cope.
Per buildfarm member curculio.
Robert Haas [Wed, 5 Oct 2016 12:04:52 +0000 (08:04 -0400)]
Rename WAIT_* constants to PG_WAIT_*.
Windows apparently has a constant named WAIT_TIMEOUT, and some of these
other names are pretty generic, too. Insert "PG_" at the front of each
name in order to disambiguate.
Tom Lane [Tue, 4 Oct 2016 21:49:07 +0000 (17:49 -0400)]
Avoid direct cross-module links in hstore_plperl and ltree_plpython, too.
Just turning the crank on the project started in commit d51924be8.
These cases turn out to be exact subsets of the boilerplate needed
for hstore_plpython.
Tom Lane [Tue, 4 Oct 2016 19:23:02 +0000 (15:23 -0400)]
Improve (I hope) our autolocation of the Python shared library.
Older versions of Python produce garbage (or at least useless) values of
get_config_vars('LDLIBRARY'). Newer versions produce garbage (or at least
useless) values of get_config_vars('SO'), which was defeating our configure
logic that attempted to identify where the Python shlib really is. The net
result, at least with a stock Python 3.5 installation on macOS, was that
we were linking against a static library in the mistaken belief that it was
a shared library. This managed to work, if you count statically absorbing
libpython into plpython.so as working. But it no longer works as of commit d51924be8, because now we get separate static copies of libpython in
plpython.so and hstore_plpython.so, and those can't interoperate on the
same data. There are some other infelicities like assuming that nobody
ever installs a private version of Python on a macOS machine.
Hence, forget about looking in $python_configdir for the Python shlib;
as far as I can tell no version of Python has ever put one there, and
certainly no currently-supported version does. Also, rather than relying
on get_config_vars('SO'), just try all the possibilities for shlib
extensions. Also, rather than trusting Py_ENABLE_SHARED, believe we've
found a shlib only if it has a recognized extension. Last, explicitly
cope with the possibility that the shlib is really in /usr/lib and
$python_libdir is a red herring --- this is the actual situation on older
macOS, but we were only accidentally working with it.
Robert Haas [Tue, 4 Oct 2016 15:49:09 +0000 (11:49 -0400)]
Remove trailing commas from enums.
Buildfarm member mylodon doesn't like them. Actually, I don't like
them either, but I failed to notice these before pushing commit 6f3bd98ebfc008cbd676da777bb0b2376c4c4bfa.
Robert Haas [Tue, 4 Oct 2016 14:50:13 +0000 (10:50 -0400)]
Extend framework from commit 53be0b1ad to report latch waits.
WaitLatch, WaitLatchOrSocket, and WaitEventSetWait now taken an
additional wait_event_info parameter; legal values are defined in
pgstat.h. This makes it possible to uniquely identify every point in
the core code where we are waiting for a latch; extensions can pass
WAIT_EXTENSION.
Because latches were the major wait primitive not previously covered
by this patch, it is now possible to see information in
pg_stat_activity on a large number of important wait events not
previously addressed, such as ClientRead, ClientWrite, and SyncRep.
Unfortunately, many of the wait events added by this patch will fail
to appear in pg_stat_activity because they're only used in background
processes which don't currently appear in pg_stat_activity. We should
fix this either by creating a separate view for such information, or
else by deciding to include them in pg_stat_activity after all.
Michael Paquier and Robert Haas, reviewed by Alexander Korotkov and
Thomas Munro.
Tom Lane [Tue, 4 Oct 2016 13:38:43 +0000 (09:38 -0400)]
Fix hstore_plpython for Python 3.
In commit d51924be8, I overlooked the need to provide linkage for
PLyUnicode_FromStringAndSize, because that's only used (and indeed
only exists) in Python 3 builds.
In light of the need to #if this item, rearrange the ordering of
the code related to each function pointer, so as not to need more
#if's than absolutely necessary.
Andres Freund [Tue, 4 Oct 2016 05:11:36 +0000 (22:11 -0700)]
Correct logical decoding restore behaviour for subtransactions.
Before initializing iteration over a subtransaction's changes, the last
few changes were not spilled to disk. That's correct if the transaction
didn't spill to disk, but otherwise... This bug can lead to missed or
misorderd subtransaction contents when they were spilled to disk.
Move spilling of the remaining in-memory changes to
ReorderBufferIterTXNInit(), where it can easily be applied to the top
transaction and, if present, subtransactions.
Since this code had too many bugs already, noticeably increase test
coverage.
Fixes: #14319 Reported-By: Huan Ruan
Discussion: <20160909012610.20024.58169@wrigleys.postgresql.org>
Backport: 9,4-, where logical decoding was added
Tom Lane [Tue, 4 Oct 2016 02:27:11 +0000 (22:27 -0400)]
Convert contrib/hstore_plpython to not use direct linking to other modules.
Previously, on most platforms, we allowed hstore_plpython's references
to hstore and plpython to be unresolved symbols at link time, trusting
the dynamic linker to resolve them when the module is loaded. This
has a number of problems, the worst being that the dynamic linker
does not know where the references come from and can do nothing but
fail if those other modules haven't been loaded. We've more or less
gotten away with that for the limited use-case of datatype transform
modules, but even there, it requires some awkward hacks, most recently
commit 83c249200.
Instead, let's not treat these references as linker-resolvable at all,
but use function pointers that are manually filled in by the module's
_PG_init function. There are few enough contact points that this
doesn't seem unmaintainable, at least for these use-cases. (Note that
the same technique wouldn't work at all for decoupling from libpython
itself, but fortunately that's just a standard shared library and can
be linked to normally.)
This is an initial patch that just converts hstore_plpython. If the
buildfarm doesn't find any fatal problems, I'll work on the other
transform modules soon.
Tom Lane [Mon, 3 Oct 2016 20:40:05 +0000 (16:40 -0400)]
Show a sensible value in pg_settings.unit for GUC_UNIT_XSEGS variables.
Commit 88e982302 invented GUC_UNIT_XSEGS for min_wal_size and max_wal_size,
but neglected to make it display sensibly in pg_settings.unit (by adding a
case to the switch in GetConfigOptionByNum). Fix that, and adjust said
switch to throw a run-time error the next time somebody forgets.
In passing, avoid using a static buffer for the output string --- the rest
of this function pstrdup's from a local buffer, and I see no very good
reason why the units code should do it differently and less safely.
Per report from Otar Shavadze. Back-patch to 9.5 where the new unit type
was added.
Stephen Frost [Mon, 3 Oct 2016 20:22:57 +0000 (16:22 -0400)]
Fix RLS with COPY (col1, col2) FROM tab
Attempting to COPY a subset of columns from a table with RLS enabled
would fail due to an invalid query being constructed (using a single
ColumnRef with the list of fields to exact in 'fields', but that's for
the different levels of an indirection for a single column, not for
specifying multiple columns).
Correct by building a ColumnRef and then RestTarget for each column
being requested and then adding those to the targetList for the select
query. Include regression tests to hopefully catch if this is broken
again in the future.
Patch-By: Adam Brightwell Reviewed-By: Michael Paquier
Tom Lane [Mon, 3 Oct 2016 14:07:39 +0000 (10:07 -0400)]
Enforce a specific order for probing library loadability in pg_upgrade.
pg_upgrade checks whether all the shared libraries used in the old cluster
are also available in the new one by issuing LOAD for each library name.
Previously, it cared not what order it did the LOADs in. Ideally it
should not have to care, but currently the transform modules in contrib
fail unless both the language and datatype modules they depend on are
loaded first. A backend-side solution for that looks possible but
probably not back-patchable, so as a stopgap measure, let's do the LOAD
tests in order by library name length. That should fix the problem for
reasonably-named transform modules, eg "hstore_plpython" will be loaded
after both "hstore" and "plpython". (Yeah, it's a hack.)
In a larger sense, having a predictable order of these probes is a good
thing, since it will make upgrades predictably work or not work in the
face of inter-library dependencies. Also, this patch replaces O(N^2)
de-duplication logic with O(N log N) logic, which could matter in
installations with very many databases. So I don't foresee reverting this
even after we have a proper fix for the library-dependency problem.
In passing, improve a couple of SQL queries used here.
Per complaint from Andrew Dunstan that pg_upgrade'ing the transform contrib
modules failed. Back-patch to 9.5 where transform modules were introduced.
Change the way pre-reading in external sort's merge phase works.
Don't pre-read tuples into SortTuple slots during merge. Instead, use the
memory for larger read buffers in logtape.c. We're doing the same number
of READTUP() calls either way, but managing the pre-read SortTuple slots
is much more complicated. Also, the on-tape representation is more compact
than SortTuples, so we can fit more pre-read tuples into the same amount
of memory this way. And we have better cache-locality, when we use just a
small number of SortTuple slots.
Now that we only hold one tuple from each tape in the SortTuple slots, we
can greatly simplify the "batch memory" management. We now maintain a
small set of fixed-sized slots, to hold the tuples, and fall back to
palloc() for larger tuples. We use this method during all merge phases,
not just the final merge, and also when randomAccess is requested, and
also in the TSS_SORTEDONTAPE case. In other words, it's used whenever we
do an external sort.
Tom Lane [Sun, 2 Oct 2016 18:31:28 +0000 (14:31 -0400)]
Add ALTER EXTENSION ADD/DROP ACCESS METHOD, and use it in pg_upgrade.
Without this, an extension containing an access method is not properly
dumped/restored during pg_upgrade --- the AM ends up not being a member
of the extension after upgrading.
Another oversight in commit 473b93287, reported by Andrew Dunstan.
Tom Lane [Sun, 2 Oct 2016 16:33:46 +0000 (12:33 -0400)]
Avoid leaking FDs after an fsync failure.
Fixes errors introduced in commit bc34223bc, as detected by Coverity.
In passing, report ENOSPC for a short write while padding a new wal file in
open_walfile, make certain that close_walfile closes walfile in all cases,
and improve a couple of comments.
Tom Lane [Sat, 1 Oct 2016 21:15:09 +0000 (17:15 -0400)]
Do ClosePostmasterPorts() earlier in SubPostmasterMain().
In standard Unix builds, postmaster child processes do ClosePostmasterPorts
immediately after InitPostmasterChild, that is almost immediately after
being spawned. This is important because we don't want children holding
open the postmaster's end of the postmaster death watch pipe.
However, in EXEC_BACKEND builds, SubPostmasterMain was postponing this
responsibility significantly, in order to make it slightly more convenient
to pass the right flag value to ClosePostmasterPorts. This is bad,
particularly seeing that process_shared_preload_libraries() might invoke
nearly-arbitrary code. Rearrange so that we do it as soon as we've
fetched the socket FDs via read_backend_variables().
Also move the comment explaining about randomize_va_space to before the
call of PGSharedMemoryReAttach, which is where it's relevant. The old
placement was appropriate when the reattach happened inside
CreateSharedMemoryAndSemaphores, but that was a long time ago.
Back-patch to 9.3; the patch doesn't apply cleanly before that, and
it doesn't seem worth a lot of effort given that we've had no actual
field complaints traceable to this.
Tom Lane [Sat, 1 Oct 2016 20:32:54 +0000 (16:32 -0400)]
Fix bugs in contrib/pg_visibility.
collect_corrupt_items() failed to initialize tuple.t_self. While
HeapTupleSatisfiesVacuum() doesn't actually use that value, it does
Assert that it's valid, so that the code would dump core if ip_posid
chanced to be zero. (That's somewhat unlikely, which probably explains
how this got missed. In any case it wouldn't matter for field use.)
Also, collect_corrupt_items was returning the wrong TIDs, that is the
contents of t_ctid rather than the tuple's own location. This would
be the same thing in simple cases, but it could be wrong if, for
example, a past update attempt had been rolled back, leaving a live
tuple whose t_ctid doesn't point at itself.
Also, in pg_visibility(), guard against trying to read a page past
the end of the rel. The VM code handles inquiries beyond the end
of the map by silently returning zeroes, and it seems like we should
do the same thing here.
I ran into the assertion failure while using pg_visibility to check
pg_upgrade's behavior, and then noted the other problems while
reading the code.
Tom Lane [Sat, 1 Oct 2016 17:45:16 +0000 (13:45 -0400)]
Fix misstatement in comment in Makefile.shlib.
There is no need for "all: all-lib" to be placed before inclusion of
Makefile.shlib. Makefile.global is what ensures that "all" is the
default target, and we already document that that has to be included
first. Per comment from Pavel Raiskup.
Tom Lane [Sat, 1 Oct 2016 17:35:13 +0000 (13:35 -0400)]
Fix misplacement of submake-generated-headers prerequisites.
The sequence "configure; cd src/pl/plpython; make -j" failed due to
trying to compile plpython's .o files before the generated headers
finished building. (This is an important real-world case, since it's
the typical second step when building both plpython2 and plpython3.)
This happens because the submake-generated-headers target is not
placed in a way to make it a prerequisite to compiling the .o files.
Fix that.
Checking other uses of submake-generated-headers, I noted that the one
attached to pg_regress was similarly misplaced; but it's actually not
needed at all for pg_regress.o, rather regress.o, so move it to be a
prerequisite of that.
Back-patch to 9.6 where submake-generated-headers was introduced
(by commit 548af97fc). It's not immediately clear to me why the
previous coding didn't have the same issue; but since we've not
had field reports of plpython make failing, leave it alone in the
older branches.
Peter Eisentraut [Fri, 30 Sep 2016 16:00:00 +0000 (12:00 -0400)]
Set log_line_prefix and application name in test drivers
Before pg_regress runs psql, set the application name to the test name.
Similarly, set the application name to the test file name in the TAP
tests. Also, set a default log_line_prefix that show the application
name, as well as the PID and a time stamp.
That way, the server log output can be correlated to the test input
files, making debugging a bit easier.
Tom Lane [Sat, 1 Oct 2016 00:40:27 +0000 (20:40 -0400)]
Improve error reporting in pg_upgrade's file copying/linking/rewriting.
The previous design for this had copyFile(), linkFile(), and
rewriteVisibilityMap() returning strerror strings, with the caller
producing one-size-fits-all error messages based on that. This made it
impossible to produce messages that described the failures with any degree
of precision, especially not short-read problems since those don't set
errno at all.
Since pg_upgrade has no intention of continuing after any error in this
area, let's fix this by just letting these functions call pg_fatal() for
themselves, making it easy for each point of failure to have a suitable
error message. Taking this approach also allows dropping cleanup code
that was unnecessary and was often rather sloppy about preserving errno.
To not lose relevant info that was reported before, pass in the schema name
and table name of the current table so that they can be included in the
error reports.
An additional problem was the use of getErrorText(), which was flat out
wrong for all but a couple of call sites, because it unconditionally did
"_dosmaperr(GetLastError())" on Windows. That's only appropriate when
reporting an error from a Windows-native API, which only a couple of
the callers were actually doing. Thus, even the reported strerror string
would be unrelated to the actual failure in many cases on Windows.
To fix, get rid of getErrorText() altogether, and just have call sites
do strerror(errno) instead, since that's the way all the rest of our
frontend programs do it. Add back the _dosmaperr() calls in the two
places where that's actually appropriate.
In passing, make assorted messages hew more closely to project style
guidelines, notably by removing initial capitals in not-complete-sentence
primary error messages. (I didn't make any effort to clean up places
I didn't have another reason to touch, though.)
Per discussion of a report from Thomas Kellerer. Back-patch to 9.6,
but no further; given the relative infrequency of reports of problems
here, it's not clear it's worth adapting the patch to older branches.
Patch by me, but with credit to Alvaro Herrera for spotting the issue
with getErrorText's misuse of _dosmaperr().
Tom Lane [Sat, 1 Oct 2016 00:39:00 +0000 (20:39 -0400)]
Fix multiple portability issues in pg_upgrade's rewriteVisibilityMap().
This is new code in 9.6, and evidently we missed out testing it as
thoroughly as it should have been. Bugs fixed here:
1. Use binary not text mode to open the files on Windows. Before, if
the visibility map chanced to contain two bytes that looked like \r\n,
Windows' read() would convert that to \n, which both corrupts the map
data and causes the file to look shorter than it should. Unless you
were *very* unlucky and had an exact multiple of 8K such occurrences
in each VM file, this would cause pg_upgrade to report a failure,
though with a rather obscure error message.
2. The code for copying rebuilt bytes into the output was simply wrong.
It chanced to work okay on little-endian machines but would emit the
bytes in the wrong order on big-endian, leading to silent corruption
of the visibility map data.
3. The code was careless about alignment of the working buffers. Given
all three of an alignment-picky architecture, a compiler that chooses
to put the new_vmbuf[] local variable at an odd starting address, and
a checksum-enabled database, pg_upgrade would dump core.
Point one was reported by Thomas Kellerer, the other two detected by
code-reading.
Point two is much the nastiest of these issues from an impact standpoint,
though fortunately it affects only a minority of users. The Windows issue
will definitely bite people, but it seems quite unlikely that there would
be undetected corruption from that.
In addition, I failed to resist the temptation to do some minor cosmetic
adjustments, mostly improving the comments.
It would be a good idea to try to improve the error reporting here, but
that seems like material for a separate patch.
Magnus Hagander [Fri, 30 Sep 2016 09:19:30 +0000 (11:19 +0200)]
Retry opening new segments in pg_xlogdump --folllow
There is a small window between when the server closes out the existing
segment and the new one is created. Put a loop around the open call in
this case to make sure we wait for the new file to actually appear.
Stephen Frost [Fri, 30 Sep 2016 02:13:38 +0000 (22:13 -0400)]
Remove superuser checks in pgstattuple
Now that we track initial privileges on extension objects and changes to
those permissions, we can drop the superuser() checks from the various
functions which are part of the pgstattuple extension and rely on the
GRANT system to control access to those functions.
Since a pg_upgrade will preserve the version of the extension which
existed prior to the upgrade, we can't simply modify the existing
functions but instead need to create new functions which remove the
checks and update the SQL-level functions to use the new functions
(and to REVOKE EXECUTE rights on those functions from PUBLIC).
Thanks to Tom and Andres for adding support for extensions to follow
update paths (see: 40b449a), allowing this patch to be much smaller
since no new base version script needed to be included.
Tom Lane [Thu, 29 Sep 2016 17:32:27 +0000 (13:32 -0400)]
Allow contrib/file_fdw to read from a program, like COPY FROM PROGRAM.
This patch just exposes COPY's FROM PROGRAM option in contrib/file_fdw.
There don't seem to be any security issues with that that are any worse
than what already exist with file_fdw and COPY; as in the existing cases,
only superusers are allowed to control what gets executed.
A regression test case might be nice here, but choosing a 100% portable
command to run is hard. (We haven't got a test for COPY FROM PROGRAM
itself, either.)
Corey Huinker and Adam Gomaa, reviewed by Amit Langote
Don't bother to lock bufmgr partitions in pg_buffercache.
That makes the view a lot less disruptive to use on a production system.
Without the locks, you don't get a consistent snapshot across all buffers,
but that's OK. It wasn't a very useful guarantee in practice.
Ivan Kartyshov, reviewed by Tomas Vondra and Robert Haas.
Peter Eisentraut [Wed, 28 Sep 2016 16:00:00 +0000 (12:00 -0400)]
Exclude additional directories in pg_basebackup
The list of files and directories that pg_basebackup excludes from the
backup was somewhat incomplete and unorganized. Change that with having
the exclusion driven from tables. Clean up some code around it. Also
document the exclusions in more detail so that users of pg_start_backup
can make use of it as well.
The contents of these directories are now excluded from the backup:
pg_dynshmem, pg_notify, pg_serial, pg_snapshots, pg_subtrans
Also fix a bug that a pg_repl_slot or pg_stat_tmp being a symlink would
cause a corrupt tar header to be created. Now such symlinks are
included in the backup as empty directories. Bug found by Ashutosh
Sharma <ashu.coek88@gmail.com>.
From: David Steele <david@pgmasters.net> Reviewed-by: Michael Paquier <michael.paquier@gmail.com>
Tom Lane [Wed, 28 Sep 2016 21:08:40 +0000 (17:08 -0400)]
Rationalize format-picture caching logic in formatting.c.
Add a validity flag to DCHCacheEntry and NUMCacheEntry entries, and
do not set it true until after we've parsed the supplied format string.
This allows dealing with possible errors while parsing the format
without the baroque hack that was there before (which only covered
errors within NUMDesc_prepare, anyway). We can get rid of the PG_TRY in
NUMDesc_prepare, as well as last_NUMCacheEntry and NUM_cache_remove.
(Essentially, this reverts commit ff783fbae in favor of a less fragile
solution; the problems with that approach are well illustrated by later
hacking such as 55f927a46.)
In passing, define the size of these caches as DCH_CACHE_ENTRIES not
DCH_CACHE_FIELDS + 1 (whoever thought that was a good definition?)
and likewise for the NUM cache. Also const-ify format string parameters
where convenient, and merge duplicated cache lookup logic.
This is primarily driven by a proposed patch from Artur Zakirov,
which introduced some ereport's into format string parsing for
the datetime case. He proposed preventing the creation of invalid
cache entries by parsing the format string first into a local-variable
array, and then copying that to a cache entry. That seemed a bit
ugly to me, and anyway randomly different from the way the identical
problem had been solved for the numeric case. Let's make the two
sets of code more similar not less so.
I'm not sure whether we'll adopt the new error conditions Artur proposes,
but this patch seems like good code cleanup and future-proofing in any
case. The existing code is critically (and undocumented-ly) dependent on
no elog being thrown out of several nontrivial functions, which is trouble
waiting to happen, though it doesn't seem to be actively broken today.
projects / postgresql / log